Keyboard mapping corruption issue perhaps? Check Tools / Options, Environment / Keyboard. Should see a drop-down for your Keyboard mapping scheme and next to it a Reset button. Hit the reset button.
I’m not responsible for this screwing with your settings – save them prior to doing this just in case you screw the pooch.
Oh, in case the narcs out there care, I think this is a valid question and would be put out if someone voted to close it. Of course now that I’ve said that, its a certaintity, isn’t it?